ipv6 icmp

Function

The ipv6 icmp command enables the system to send or receive ICMPv6 messages.

The undo ipv6 icmp command disables the system to send or receive ICMPv6 messages.

The clear ipv6 icmp command clears the configurations of the ipv6 icmp and undo ipv6 icmp commands.

By default, a device sends or receives well-known ICMPv6 messages not other types of ICMPv6 messages.

Format

ipv6 icmp { echo-reply | echo | err-header-field | hop-limit-exceeded | neighbor-advertisement | neighbor-solicitation | network-unreachable | packet-too-big | redirect | router-advertisement | router-solicitation | multicast-listener-report-v2 | multicast-listener-query | multicast-listener-report | multicast-listener-done } { send | receive }

ipv6 icmp { frag-time-exceeded | host-admin-prohib | unknown-next-hdr } { send | receive }

ipv6 icmp unknown-ipv6-opt { send | receive }

ipv6 icmp host-unreachable { send | receive }

ipv6 icmp port-unreachable { send | receive }

ipv6 icmp icmp6Type icmp6Code { send | receive }

ipv6 icmp all-famous { send | receive }

clear ipv6 icmp { echo-reply | echo | err-header-field | hop-limit-exceeded | neighbor-advertisement | neighbor-solicitation | network-unreachable | packet-too-big | redirect | router-advertisement | router-solicitation | multicast-listener-report-v2 | multicast-listener-query | multicast-listener-report | multicast-listener-done } { send | receive }

clear ipv6 icmp { frag-time-exceeded | host-admin-prohib | unknown-next-hdr } { send | receive }

clear ipv6 icmp unknown-ipv6-opt { send | receive }

clear ipv6 icmp host-unreachable { send | receive }

clear ipv6 icmp port-unreachable { send | receive }

clear ipv6 icmp icmp6Type icmp6Code { send | receive }

clear ipv6 icmp all-famous { send | receive }

undo ipv6 icmp { echo-reply | echo | err-header-field | hop-limit-exceeded | neighbor-advertisement | neighbor-solicitation | network-unreachable | packet-too-big | redirect | router-advertisement | router-solicitation | multicast-listener-report-v2 | multicast-listener-query | multicast-listener-report | multicast-listener-done } { send | receive }

undo ipv6 icmp { frag-time-exceeded | host-admin-prohib | unknown-next-hdr } { send | receive }

undo ipv6 icmp unknown-ipv6-opt { send | receive }

undo ipv6 icmp host-unreachable { send | receive }

undo ipv6 icmp port-unreachable { send | receive }

undo ipv6 icmp icmp6Type icmp6Code { send | receive }

undo ipv6 icmp all-famous { send | receive }

Parameters

Parameter	Description	Value
echo-reply	Indicates an Echo Reply message.	-
echo	Indicates an Echo message.	-
err-header-field	Indicates an ICMPv6 error header field message.	-
hop-limit-exceeded	Indicates an ICMPv6 Hop Limit Exceeded message.	-
neighbor-advertisement	Indicates an ICMPv6 neighbor advertisement message.	-
neighbor-solicitation	Indicates an ICMPv6 neighbor solicitation message.	-
network-unreachable	Indicates an ICMPv6 Network Unreachable message.	-
packet-too-big	Indicates an ICMPv6 Packet Too Big message.	-
redirect	Indicates an ICMPv6 redirect message.	-
router-advertisement	Indicates an ICMPv6 router advertisement message.	-
router-solicitation	Indicates an ICMPv6 router solicitation message.	-
multicast-listener-report-v2	Indicates a Version 2 Multicast Listener Report message.	-
multicast-listener-query	Indicates a Multicast Listener Query message.	-
multicast-listener-report	Indicates a Multicast Listener Report message.	-
multicast-listener-done	Indicates a Multicast Listener Done message.	-
send	Enables the system to send ICMPv6 messages.	-
receive	Enables the system to receive ICMPv6 messages.	-
frag-time-exceeded	Indicates an ICMPv6 Fragment Time Exceeded message.	-
host-admin-prohib	Indicates an ICMPv6 host administratively prohibited message.	-
unknown-next-hdr	Indicates an ICMPv6 unknown Next Header type message.	-
unknown-ipv6-opt	Indicates an ICMPv6 unknown IPv6 option message.	-
host-unreachable	Indicates an ICMPv6 Host Unreachable message.	-
port-unreachable	Indicates an ICMPv6 Port Unreachable message.	-
icmp6Type	Specifies the type of an ICMPv6 message.	The value is an integer that ranges from 0 to 255.
icmp6Code	Specifies the code of an ICMPv6 message.	The value is an integer that ranges from 0 to 255.
all-famous	Indicates all-famous ICMPv6 messages, including: Sent well-known ICMPv6 messages: echo, echo-reply, hop-limit-exceeded, neighbor-advertisement, neighbor-solicitation, network-unreachable, packet-too-big, redirect, router-advertisement, router-solicitation, multicast-listener-done, multicast-listener-query, multicast-listener-report, multicast-listener-report-v2, host-unreachable, and port-unreachable. Received well-known ICMPv6 messages: echo, echo-reply, hop-limit-exceeded, neighbor-advertisement, neighbor-solicitation, packet-too-big, router-advertisement, router-solicitation, multicast-listener-done, multicast-listener-query, multicast-listener-report, multicast-listener-report-v2, and port-unreachable.	-

Views

System view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
ip-stack	write

Usage Guidelines

Usage Scenario

On a normal network, a device can correctly send or receive ICMPv6 messages; however, when network traffic load is heavy, host unreachable or port unreachable events frequently occur and routers need to send a large number of ICMPv6 messages, which burdens the network and degrades the performance of the routers. In addition, attackers usually use ICMPv6 error messages to probe the internal network topology illegitimately.

To improve network performance and security, run the undo ipv6 icmp command to disable routing devices from sending or receiving ICMPv6 messages of specified types, such as Echo Reply, Host Unreachable, and Port Unreachable messages. If all-famous, ND-related parameters, or MLD-related parameters are specified, exercise caution when running this command. Otherwise, IPv6 unicast services (ND) or multicast services (MLD) may be affected.

all-famous: disables the system from sending or receiving all well-known ICMPv6 messages.
ND-related parameters: neighbor-advertisement, neighbor-solicitation, router-advertisement, router-solicitation, and redirect.
MLD-related parameters: multicast-listener-report-v2, multicast-listener-query, multicast-listener-report, and multicast-listener-done.
If you want to restore the default configuration and the display this command output does not contain the ipv6 icmp or undo ipv6 icmp command configuration, run the clear ipv6 icmp command.

Configuration Impact

After the system is disabled from sending or receiving ICMPv6 Echo-Reply messages, Host-Unreachable messages, and Port-Unreachable messages, the system counts only the number of discarded messages instead of the number of sent or receive Echo-Reply messages, Host-Unreachable messages, and Port-Unreachable messages.

Precautions

When the network becomes normal again, you can run the ipv6 icmp command to re-enable the system to process ICMPv6 messages.

Example

# Disable the system from sending ICMPv6 reply packets.

<HUAWEI> system-view
[~HUAWEI] undo ipv6 icmp echo-reply send

# Enable the system to send ICMPv6 redirection packets.

<HUAWEI> system-view
[~HUAWEI] ipv6 icmp redirect send

# Enable the system to send ICMPv6 reply packets.

<HUAWEI> system-view
[~HUAWEI] ipv6 icmp echo-reply send